LAWRENCE — It’s hard to exaggerate the importance of rivers to sustaining life for animals and people. Rivers provide drinking water, food, crop irrigation, recreation and even regulation of air temperatures.
But until recently, much scientific inquiry into river systems has focused on the small scale: looking at water quality in specific river areas or investigating populations of individual river species, for instance. As the influence of climate change takes hold, however, understanding the condition of large riverine “macrosystems” that support life across entire regions is increasingly important.
Now, a five-year, $4.2 million grant from the National Science Foundation will empower researchers from multiple institutions in the U.S. and Mongolia to develop wide-ranging scientific knowledge of river systems spanning two continents. Of that grant, half of the funds will support work at the University of Kansas, the lead institution on the project.
“River macrosystems represent larger spatial areas than studied in the typical ecosystem or landscape study,” said James Thorp, KU professor of ecology and evolutionary biology and senior scientist with the Kansas Biological Survey, who is the lead principal investigator on the new grant. “In our case, we’re studying river macrosystems within ecoregions — mountain steppes, grasslands, desert shrub-forests — enclosed within temperate steppe biomes distributed in the U.S. in North America and Mongolia in Asia.”
Thorp said he and his co-investigators are interested in the importance to ecological processes at different spatial scales — ecoregions down to valley-scale patches within rivers, dubbed “Functional Process Zones” — and how they interact. “For example, what are the appropriate scales to study system metabolism, food webs and biodiversity traits within macrosystems?” he said.
Researchers will sample nine rivers spread between the U.S. Great Plains, Great Basin and Mountain Steppes. These include the Platte, Niobrara, Humboldt, Bear and Snake rivers, among others. In Mongolia, they’ll investigate nine rivers within similar ecoregions as those in the U.S.
Thorp said that studies of each continent could reveal the future of the other: North American river systems, with their dams and presence of non-native fauna, could foreshadow the future of rivers in Mongolia; in turn Mongolia, which has “one of the strongest warming signals in the North Temperate Zone,” could indicate changes U.S. rivers will undergo in a future of boosted temperatures.
“Mongolia offers us the ability to look at rivers which have not been unduly altered by dams or introduced species and ask what will happen if our climate changes much more in the future,” Thorp said.
Under sway of a changing climate, the KU researcher said that scientific expectations for Great Plains rivers include more erratic precipitation that brings greater flow and floods along with droughts and higher temperatures.
“Organisms living in our mostly easterly and somewhat southerly flowing rivers could find it difficult to escape rising temperatures because they will have to swim long distances to reach a pathway north to cooler temperatures,” Thorp said. “Those in rivers flowing from the south to the north — like the Red River of Minnesota and the Dakotas — or flowing mostly south, like the Mississippi and much of the Missouri, provide an avenue for fish to move northward to cooler waters. This process will be easier for fish living in large rivers but harder for those confined to headwater streams. Our temperatures are already increasing in the Great Plains, and the precipitation pattern may also be changing.”
Thorp has studied aquatic systems for his entire academic career as well as rivers since about 1989. While he researches other aquatic systems such as reservoirs, ephemeral wetlands and small streams, rivers are his main focus today.
“Much of my research has been on a large scale, but this surpasses anything I have tackled in my career,” he said. “In part, this reflects budgetary limitations in the past, but it also reflects the evolution of ideas many scientists experience in their careers. Large-scale research has been undertaken by a minority of scientists working on lakes, oceans, terrestrial habitats and streams, but all of us together represent a minority of the scientists in our fields.”
One of Thorp’s main jobs supervising the grant will be organizing research activities and “getting everyone and all the equipment where they need to be when we are ready for expeditions to start,” he said.
“Each expedition will involve eight to 10 scientists and students, with some overlap of people from one summer to the next,” Thorp said. “A given expedition will last probably five to six weeks, including travel to sites and back. The Mongolian expeditions will be longer because of the additional travel time for U.S. participants and additional difficulties reaching field sites from lack of paved roads — or any roads sometimes — bridges in some areas and airports in many regions.”
Thorp outlined challenging fieldwork conditions in Mongolia: “Working on Mongolian rivers is vastly more difficult from a logistical standpoint compared to working on U.S. rivers,” he said. “You have to contract with one of three outdoor travel companies specializing in field expeditions. They provide vehicles, drivers, boats, camping gear, translators — it is a Cyrillic language — cooks and general camp workers. You have to adapt to some logistical constraints, such as banks are rare, ATMs cannot be found except rarely in the capital, and our cell phones won’t work there at all or at least not outside of the capital.”
According to Thorp, teams will sample differences among sites in system metabolism (fluctuations in oxygen production by algae and plants and consumption of oxygen by bacteria, algae, plants and animals); food webs (sources of organic energy, food chain length and food web structure); biodiversity traits of fish and invertebrates (for example, feeding groups like predators, herbivores, omnivores, etc.); and physical and biological characteristics of the riparian zone and basin.
“The equipment we’ll use isn’t particularly novel,” he said. “For example, we’ll employ a standard acoustic doppler to measure flow and discharge in rivers combined with data sondes that measure oxygen content of the water; together, they’ll enable us to determine ecosystem metabolism — from algal production of oxygen and consumption of oxygen by all living organisms from bacteria and algae [at night] to fish. We’ll use backpack and boat-mounted electro-fishing gear as well as nets and seines to collect fish for tissue samples. Some of the fish tissue samples, such as fin clips, will be analyzed for amino acid stable isotope analysis — a very new technique — to evaluate food webs in these rivers. Invertebrates will be collected by hand and with sweep nets.”
Using results from the field, Thorp then will oversee compilation of all data and information, and see that resulting syntheses and conclusions are available for team members to publish in journals and present to science conferences, governments and the public.
“Weaving all the information together will require the intellectual abilities of most of the scientists and graduate students involved in the project,” he said. “Different people will have different focal areas. Some of us who enjoy looking at large-scale concepts will have primary roles in bringing much of the ideas together and building a coherent picture of the whole.”
National Science Foundation’s Macrosystem Biology program in the Division of Environmental Biology is supporting this work. KU provided a vital grant of more than $20,000 for a February 2014 workshop that brought together scientists from the U.S., Mongolia and France to develop the ideas for this proposal.
Co-principal investigators on the project are Mark Pyron, Ball State University; Jon Gelhaus and Alain Maasri, Academy of Natural Sciences of Drexel University; Walter Dodds, Kansas State University; Bazartseren Boldgiv, National University of Mongolia; Olaf Jensen, Rutgers University; Scott Kenner, South Dakota School of Mines and Technology; Dan Reuman, University of Kansas; Sudeep Chandra, University of Nevada Reno; and Barbara Hayford, Wayne State College.